The following constitutes approximately 75% of total immunoglobin in humans -

IgG is the main serum immunoglobulin consisting of 80% of the total. equally distributed between intravascular and extravascular compaments. The normal serum concentration of IgG is about 8-16 mg per ml. Reference : Anathanarayan & paniker's 9th edition, pg no: 96, <\p>